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The Biogeochemical Role of Baleen Whales and Krill in Southern Ocean Nutrient Cycling


Ratnarajah, L and Bowie, AR and Lannuzel, D and Meiners, K and Nicol, S, The Biogeochemical Role of Baleen Whales and Krill in Southern Ocean Nutrient Cycling, PLoS ONE, 9, (12) Article e114067. ISSN 1932-6203 (2014) [Refereed Article]


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Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0)

DOI: doi:10.1371/journal.pone.0114067


The availability of micronutrients is a key factor that affects primary productivity in High Nutrient Low Chlorophyll (HNLC) regions of the Southern Ocean. Nutrient supply is governed by a range of physical, chemical and biological processes, and there are significant feedbacks within the ecosystem. It has been suggested that baleen whales form a crucial part of biogeochemical cycling processes through the consumption of nutrient-rich krill and subsequent defecation, but data on their contribution are scarce. We analysed the concentration of iron, cadmium, manganese, cobalt, copper, zinc, phosphorus and carbon in baleen whale faeces and muscle, and krill tissue using inductively coupled plasma mass spectrometry. Metal concentrations in krill tissue were between 20 thousand and 4.8 million times higher than typical Southern Ocean HNLC seawater concentrations, while whale faecal matter was between 276 thousand and 10 million times higher. These findings suggest that krill act as a mechanism for concentrating and retaining elements in the surface layer, which are subsequently released back into the ocean, once eaten by whales, through defecation. Trace metal to carbon ratios were also higher in whale faeces compared to whale muscle indicating that whales are concentrating carbon and actively defecating trace elements. Consequently, recovery of the great whales may facilitate the recycling of nutrients via defecation, which may affect productivity in HNLC areas.

Item Details

Item Type:Refereed Article
Keywords:biogeochemistry, Baleen Whales, Krill, Southern Ocean Nutrient Cycling
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Biological oceanography
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Biodiversity in Antarctic and Southern Ocean environments
UTAS Author:Ratnarajah, L (Dr Lavenia Ratnarajah)
UTAS Author:Bowie, AR (Professor Andrew Bowie)
UTAS Author:Lannuzel, D (Associate Professor Delphine Lannuzel)
UTAS Author:Meiners, K (Dr Klaus Meiners)
UTAS Author:Nicol, S (Dr Stephen Nicol)
ID Code:97460
Year Published:2014
Web of Science® Times Cited:44
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2014-12-17
Last Modified:2017-10-31
Downloads:473 View Download Statistics

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